--- /dev/null
+/*
+ * drivers/uio/uio_dmem_genirq.c
+ *
+ * Userspace I/O platform driver with generic IRQ handling code.
+ *
+ * Copyright (C) 2012 Damian Hobson-Garcia
+ *
+ * Based on uio_pdrv_genirq.c by Magnus Damm
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/uio_driver.h>
+#include <linux/spinlock.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/platform_data/uio_dmem_genirq.h>
+#include <linux/stringify.h>
+#include <linux/pm_runtime.h>
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+
+#define DRIVER_NAME "uio_dmem_genirq"
+#define DMEM_MAP_ERROR (~0)
+
+struct uio_dmem_genirq_platdata {
+ struct uio_info *uioinfo;
+ spinlock_t lock;
+ unsigned long flags;
+ struct platform_device *pdev;
+ unsigned int dmem_region_start;
+ unsigned int num_dmem_regions;
+ void *dmem_region_vaddr[MAX_UIO_MAPS];
+ struct mutex alloc_lock;
+ unsigned int refcnt;
+};
+
+static int uio_dmem_genirq_open(struct uio_info *info, struct inode *inode)
+{
+ struct uio_dmem_genirq_platdata *priv = info->priv;
+ struct uio_mem *uiomem;
+ int ret = 0;
+ int dmem_region = priv->dmem_region_start;
+
+ uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
+
+ mutex_lock(&priv->alloc_lock);
+ while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
+ void *addr;
+ if (!uiomem->size)
+ break;
+
+ addr = dma_alloc_coherent(&priv->pdev->dev, uiomem->size,
+ (dma_addr_t *)&uiomem->addr, GFP_KERNEL);
+ if (!addr) {
+ uiomem->addr = DMEM_MAP_ERROR;
+ }
+ priv->dmem_region_vaddr[dmem_region++] = addr;
+ ++uiomem;
+ }
+ priv->refcnt++;
+
+ mutex_unlock(&priv->alloc_lock);
+ /* Wait until the Runtime PM code has woken up the device */
+ pm_runtime_get_sync(&priv->pdev->dev);
+ return ret;
+}
+
+static int uio_dmem_genirq_release(struct uio_info *info, struct inode *inode)
+{
+ struct uio_dmem_genirq_platdata *priv = info->priv;
+ struct uio_mem *uiomem;
+ int dmem_region = priv->dmem_region_start;
+
+ /* Tell the Runtime PM code that the device has become idle */
+ pm_runtime_put_sync(&priv->pdev->dev);
+
+ uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
+
+ mutex_lock(&priv->alloc_lock);
+
+ priv->refcnt--;
+ while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
+ if (!uiomem->size)
+ break;
+ if (priv->dmem_region_vaddr[dmem_region]) {
+ dma_free_coherent(&priv->pdev->dev, uiomem->size,
+ priv->dmem_region_vaddr[dmem_region],
+ uiomem->addr);
+ }
+ uiomem->addr = DMEM_MAP_ERROR;
+ ++dmem_region;
+ ++uiomem;
+ }
+
+ mutex_unlock(&priv->alloc_lock);
+ return 0;
+}
+
+static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
+{
+ struct uio_dmem_genirq_platdata *priv = dev_info->priv;
+
+ /* Just disable the interrupt in the interrupt controller, and
+ * remember the state so we can allow user space to enable it later.
+ */
+
+ if (!test_and_set_bit(0, &priv->flags))
+ disable_irq_nosync(irq);
+
+ return IRQ_HANDLED;
+}
+
+static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
+{
+ struct uio_dmem_genirq_platdata *priv = dev_info->priv;
+ unsigned long flags;
+
+ /* Allow user space to enable and disable the interrupt
+ * in the interrupt controller, but keep track of the
+ * state to prevent per-irq depth damage.
+ *
+ * Serialize this operation to support multiple tasks.
+ */
+
+ spin_lock_irqsave(&priv->lock, flags);
+ if (irq_on) {
+ if (test_and_clear_bit(0, &priv->flags))
+ enable_irq(dev_info->irq);
+ } else {
+ if (!test_and_set_bit(0, &priv->flags))
+ disable_irq(dev_info->irq);
+ }
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ return 0;
+}
+
+static int uio_dmem_genirq_probe(struct platform_device *pdev)
+{
+ struct uio_dmem_genirq_pdata *pdata = dev_get_platdata(&pdev->dev);
+ struct uio_info *uioinfo = &pdata->uioinfo;
+ struct uio_dmem_genirq_platdata *priv;
+ struct uio_mem *uiomem;
+ int ret = -EINVAL;
+ int i;
+
+ if (pdev->dev.of_node) {
+ int irq;
+
+ /* alloc uioinfo for one device */
+ uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL);
+ if (!uioinfo) {
+ ret = -ENOMEM;
+ dev_err(&pdev->dev, "unable to kmalloc\n");
+ goto bad2;
+ }
+ uioinfo->name = pdev->dev.of_node->name;
+ uioinfo->version = "devicetree";
+
+ /* Multiple IRQs are not supported */
+ irq = platform_get_irq(pdev, 0);
+ if (irq == -ENXIO)
+ uioinfo->irq = UIO_IRQ_NONE;
+ else
+ uioinfo->irq = irq;
+ }
+
+ if (!uioinfo || !uioinfo->name || !uioinfo->version) {
+ dev_err(&pdev->dev, "missing platform_data\n");
+ goto bad0;
+ }
+
+ if (uioinfo->handler || uioinfo->irqcontrol ||
+ uioinfo->irq_flags & IRQF_SHARED) {
+ dev_err(&pdev->dev, "interrupt configuration error\n");
+ goto bad0;
+ }
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv) {
+ ret = -ENOMEM;
+ dev_err(&pdev->dev, "unable to kmalloc\n");
+ goto bad0;
+ }
+
+ dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
+
+ priv->uioinfo = uioinfo;
+ spin_lock_init(&priv->lock);
+ priv->flags = 0; /* interrupt is enabled to begin with */
+ priv->pdev = pdev;
+ mutex_init(&priv->alloc_lock);
+
+ if (!uioinfo->irq) {
+ ret = platform_get_irq(pdev, 0);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to get IRQ\n");
+ goto bad1;
+ }
+ uioinfo->irq = ret;
+ }
+ uiomem = &uioinfo->mem[0];
+
+ for (i = 0; i < pdev->num_resources; ++i) {
+ struct resource *r = &pdev->resource[i];
+
+ if (r->flags != IORESOURCE_MEM)
+ continue;
+
+ if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
+ dev_warn(&pdev->dev, "device has more than "
+ __stringify(MAX_UIO_MAPS)
+ " I/O memory resources.\n");
+ break;
+ }
+
+ uiomem->memtype = UIO_MEM_PHYS;
+ uiomem->addr = r->start;
+ uiomem->size = resource_size(r);
+ ++uiomem;
+ }
+
+ priv->dmem_region_start = i;
+ priv->num_dmem_regions = pdata->num_dynamic_regions;
+
+ for (i = 0; i < pdata->num_dynamic_regions; ++i) {
+ if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
+ dev_warn(&pdev->dev, "device has more than "
+ __stringify(MAX_UIO_MAPS)
+ " dynamic and fixed memory regions.\n");
+ break;
+ }
+ uiomem->memtype = UIO_MEM_PHYS;
+ uiomem->addr = DMEM_MAP_ERROR;
+ uiomem->size = pdata->dynamic_region_sizes[i];
+ ++uiomem;
+ }
+
+ while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
+ uiomem->size = 0;
+ ++uiomem;
+ }
+
+ /* This driver requires no hardware specific kernel code to handle
+ * interrupts. Instead, the interrupt handler simply disables the
+ * interrupt in the interrupt controller. User space is responsible
+ * for performing hardware specific acknowledge and re-enabling of
+ * the interrupt in the interrupt controller.
+ *
+ * Interrupt sharing is not supported.
+ */
+
+ uioinfo->handler = uio_dmem_genirq_handler;
+ uioinfo->irqcontrol = uio_dmem_genirq_irqcontrol;
+ uioinfo->open = uio_dmem_genirq_open;
+ uioinfo->release = uio_dmem_genirq_release;
+ uioinfo->priv = priv;
+
+ /* Enable Runtime PM for this device:
+ * The device starts in suspended state to allow the hardware to be
+ * turned off by default. The Runtime PM bus code should power on the
+ * hardware and enable clocks at open().
+ */
+ pm_runtime_enable(&pdev->dev);
+
+ ret = uio_register_device(&pdev->dev, priv->uioinfo);
+ if (ret) {
+ dev_err(&pdev->dev, "unable to register uio device\n");
+ pm_runtime_disable(&pdev->dev);
+ goto bad1;
+ }
+
+ platform_set_drvdata(pdev, priv);
+ return 0;
+ bad1:
+ kfree(priv);
+ bad0:
+ /* kfree uioinfo for OF */
+ if (pdev->dev.of_node)
+ kfree(uioinfo);
+ bad2:
+ return ret;
+}
+
+static int uio_dmem_genirq_remove(struct platform_device *pdev)
+{
+ struct uio_dmem_genirq_platdata *priv = platform_get_drvdata(pdev);
+
+ uio_unregister_device(priv->uioinfo);
+ pm_runtime_disable(&pdev->dev);
+
+ priv->uioinfo->handler = NULL;
+ priv->uioinfo->irqcontrol = NULL;
+
+ /* kfree uioinfo for OF */
+ if (pdev->dev.of_node)
+ kfree(priv->uioinfo);
+
+ kfree(priv);
+ return 0;
+}
+
+static int uio_dmem_genirq_runtime_nop(struct device *dev)
+{
+ /* Runtime PM callback shared between ->runtime_suspend()
+ * and ->runtime_resume(). Simply returns success.
+ *
+ * In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
+ * are used at open() and release() time. This allows the
+ * Runtime PM code to turn off power to the device while the
+ * device is unused, ie before open() and after release().
+ *
+ * This Runtime PM callback does not need to save or restore
+ * any registers since user space is responsbile for hardware
+ * register reinitialization after open().
+ */
+ return 0;
+}
+
+static const struct dev_pm_ops uio_dmem_genirq_dev_pm_ops = {
+ .runtime_suspend = uio_dmem_genirq_runtime_nop,
+ .runtime_resume = uio_dmem_genirq_runtime_nop,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id uio_of_genirq_match[] = {
+ { /* empty for now */ },
+};
+MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
+#endif
+
+static struct platform_driver uio_dmem_genirq = {
+ .probe = uio_dmem_genirq_probe,
+ .remove = uio_dmem_genirq_remove,
+ .driver = {
+ .name = DRIVER_NAME,
+ .pm = &uio_dmem_genirq_dev_pm_ops,
+ .of_match_table = of_match_ptr(uio_of_genirq_match),
+ },
+};
+
+module_platform_driver(uio_dmem_genirq);
+
+MODULE_AUTHOR("Damian Hobson-Garcia");
+MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory.");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRIVER_NAME);
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